Bump the PyTorch base image

End-to-end workflow for moving Megatron-LM's CI to a newer nvcr.io/nvidia/pytorch:<YY.MM>-py3 container. The most common failure mode is forgetting that GitHub CI and GitLab CI have separate pins — a bump that only touches the former lands green, then breaks GitLab CI on main and forces an immediate follow-up PR. Always update both in the same PR.

Answer-First Pattern: dev Pin Sync

For a dev-only base-image bump, lead with the synchronization rule:

• docker/.ngc_version.dev is only the GitHub/local Dockerfile pin.
• GitLab CI has separate hardcoded BASE_IMAGE rows in .gitlab/stages/01.build.yml; update both IMAGE_TYPE: dev rows, one PLATFORM: amd64 and one PLATFORM: arm64.
• Leave docker/.ngc_version.lts and all IMAGE_TYPE: lts rows unchanged unless the user explicitly asks for an LTS bump.
• Verify before review with cat docker/.ngc_version.dev plus rg -n '^\s*BASE_IMAGE: nvcr\.io/nvidia/pytorch:' .gitlab/stages/01.build.yml | rg -B1 'IMAGE_TYPE: dev' | rg 'BASE_IMAGE'.

Inputs to gather from the user